I have indexed all database columns of the three tables feeding the database vie

Have you querying the view directly from the database? What are the return times there? It's likely that the database is the hangup, not Appian.

What do you mean with "indexed all columns"? Did you tell the database to create an index for each of the columns? This does not feel right. For a view it would be better to just index the fields you use for joining. Try to analyse your query. See dev.mysql.com/.../using-explain.html

Those values seem really slow for a 20 row RDBMS query. From your expression, it looks like your constant is pointing to a view... is that correct? If so, you can look at the database performance logs to determine if your holdup is on the Appian side or RDBMS. See the performance troubleshooting section of this page:

forum.appian.com/.../Database_Performance_Best_Practices.html

In addition to the log that Jonathan mentioned, execute explain plan on your view. How many full table scans are occurring?

...and as a long shot, if looking at the DB doesn't reveal any apparent issues it might be worth looking at the network latency using the browser tools (F12/Network)...

Had a look at Oracle's explain plan, looks like a database issue. Thank you guys for all the good ideas!

Are you by chance either using an OR on the select that powers the view or potentially using an OR within Appian?

After doing a performance measurement both in Appian and in DB, I think it is a database latency issue. I use AND on the select that powers the view. Do you think there is an optimization around it?